Lamellar mesophase nucleated by Josephson vortices at the melting of the vortex lattice in $Bi_2Sr_2CaCu_2O_{8+delta}$

TL;DR

This study reveals that Josephson vortices induce a mesomorphic phase with lamellar structures during vortex lattice melting in ext{Bi}_2 ext{Sr}_2 ext{CaCu}_2 ext{O}_{8+ ext{delta}}, with local effects far exceeding bulk changes.

Contribution

It demonstrates the local influence of Josephson vortices on vortex lattice melting, revealing a mesomorphic phase with periodic lamellas controlled by in-plane magnetic fields.

Findings

Melting begins along Josephson vortex stacks forming lamellar phases.

Local melting field reduction is over ten times larger along vortex stacks.

The lamellar structures are tunable by the in-plane magnetic field.

Abstract

The local effect of the Josephson vortices on the vortex lattice melting process in \BSCCO crystals in the presence of an in-plane field $H_{ab}$ is studied by differential magneto-optical imaging. The melting process is found to commence along the Josephson vortex stacks, forming a mesomorphic phase of periodic liquid and solid lamellas, the direction and spacing of which are controlled by $H_{ab}$. The reduction of the local melting field $H_m$ along the Josephson vortex stacks is more than an order of magnitude larger than the reduction of the average bulk $H_m$ by $H_{ab}$.